Boresighting system and method

ABSTRACT

A boresight device, includes a rotating camera and a camera carrier. The camera carrier is connected to a firearm barrel, or removably attachable to the firearm.

FIELD OF THE INVENTION

This invention relates to the field of boresight alignment in flattrajectory firearms.

BACKGROUND OF THE INVENTION

An alignment process in which the optical or electro-optical sightingsystem of a firearm is brought into correlation with the centerline axis(hereinafter ‘boresight’) of the firearm's muzzle is termedboresighting.

For an accurate aiming of a weapon's muzzle, it is required that themuzzle's boresight will be accurately correlated with the weapon'ssight. Deviating from an optimal correlation between the muzzle'sboresight and the sight's line-of-sight will probably result in missingthe target by the projectiles thus being shot.

The spatial relationship between weapons muzzle and sight is subjectedto often changes resulting from material strains, varying environmentaltemperature, thermal expansion of the weapon during firing, and othervarying factors. Maintenance procedure including boresight alignmentand/or verification should thus be carried out either periodically orwhenever an inaccuracy in the weapon's actual shooting becomesnoticeable.

In a primary stage of boresighting it is required that the imaginarycenterline axis of a muzzle's bore will be presented by comparable dataindicative of its spatial orientation. Such data may then be comparedwith respective data indicative of the spatial orientation of theline-of-sight of the weapon's sight, and the required correlation canthus be verified, or otherwise obtained by respective alignment betweenthe sight and the muzzle.

A commonly known in the art boresighting method for flat trajectoryfirearms makes use of a muzzle insert device. The insert devicecomprises a main body having contact members dimensioned to contact theinner surface of the muzzle in several spaced apart locations, so as tofixate the insert in position along a portion of the muzzle with themuzzle's axis and the insert's axis substantially overlapping or atleast extending parallel to one another. The insert further comprises atelescope having an optical reticle (e.g. cross-hair) superimposed intoits field of view. The telescope is mounted to the insert adjustably,such that its line-of-sight can be brought into a substantial alignmentwith the insert's axis. When such alignment exists, both theline-of-sight and the insert's axis will merge with the point indicatedby the telescope's cross-hair (or other pointing element) on a chosentarget. Since the muzzle's centerline axis is parallel to the insert'saxis, the indication of the cross hair (or other pointing element) onthe chosen target presents (if not exactly at least in an acceptableproximity) the intersection of the muzzle's centerline axis and thetarget. The hitting point of the muzzle's centerline axis on the targetis comparable with the hitting point of the sight's line-of-sight on thesame target, and thus, by comparing the two points the boresighting maybe completed by an adjusting step.

However, in order to enable a comparison between said two hittingpoints, cooperation between at least two operators will normally berequired. A first operator has to choose a target and to aim theweapon's sight to a predetermined point on the target. A second operatorhas to position the insert device in the muzzle, to bring thetelescope's line-of-view into alignment with the insert's axis in caseit deviates, and to communicate with the first operator in order toinform him the coordination of the boresight hitting point with respectto the chosen target. In case the sight and the muzzle have been foundout of alignment, the communication between the two operators should becontinued until alignment is obtained.

In some cases, e.g. when the boresighting is performed in fieldconditions, it may happen that none of available targets canunambiguously be agreed on both operators. In such cases, a target inthe field should be chosen and be tangibly marked by an appropriatephysical sign or pointer, so as to ensure both operators are aiming atthe same point. A third operator is therefore needed either forpositioning a noticeable target in the field or for physically markingan existing target.

In case the weapon undergoing the boresighting is of large dimensions,e.g. a tank canon, the second operator will normally require a ladderfor using the boresighting telescope during the alignment.

Although the above described method is held accurate when compared withother known methods and thus preferred by many, it is appreciated thatthe method still cumbersome, and inconvenient for the operators. Thiscan lead to mistakes and inaccuracies in boresighting due to humanerrors, especially in case the procedure should be performed understress conditions, as may often happen during the use of weapons.

WO 02/27259 suggests a method and apparatus for remote boresighting alarge caliber gun by electro-optical means, while a single user performsthe alignment in close proximity to the sight of a weapons platformcarrying the gun. A remote boresight comprised of an imager, whichincludes a TV camera, is attached either internally or externally to thegun, and used to relay a target image to the single user. The user viewsthe same target through the sight and brings die sight and the gun intoalignment. To make sure that an internal boresight (in the context of WO02/27259 the term boresight relates to a boresighting instrument) isaligned with the gun's muzzle axis, the boresiglht is rotated inside themuzzle, and a check is made that a crosshair which is normally part of,and visible through the boresight telescope, remains fixed on the samepoint of a target.

As may be understood from the WO 02/27259 publication, two mainalternatives are suggested. A first alternative is to use a fixed TVcamera attached to the muzzle externally, for imitating the muzzle'saxis. A second alternative is to use a mobile boresighting device havingan integral TV camera, to be removably inserted into the muzzle, forimitating the muzzle's axis. According to both alternatives it isnecessary to verify from time to time that there is an accuratealignment between the actual axis of the muzzle and between itsimitation, that is the line-of-view of the TV camera. This verificationwill be referred to hereinafter “calibration of boresighting equipment”.

As already mentioned, according to WO 02/27259 the calibration of theboresighting equipment includes rotating the boresight inside themuzzle, in order to check whether a crosshair visible through theboresight telescope, indicates the same point of a target, regardless ofthe rotation.

It is appreciated that the need to rotate the boresighting equipmentinside the muzzle and, if needed, the adjustment procedure to follow,are not sufficiently user friendly, and therefore, as indicated by WO02/27259 the calibration of the boresighting equipment is not to becarried out every time a muzzle's boresighting is performed.

The present invention is therefore aimed at facilitating the calibrationprocedure of boresighting equipment.

SUMMARY OF THE INVENTION

The accuracy of boresighting equipment much depends on the accurateparallelism between the muzzle's axis and the line-of-view of aboresight imaging device used for imitating the actual muzzle's axis. Assuggested by WO 02/27259, the boresight imaging device may include a TVcamera as a means for imaging the muzzle's axis.

Unfortunately, TV cameras has the problem that temperature variations,mechanical vibrations, and other factors, factually change along timethe respective positioning between the mechanical and optical componentsof the camera and between a photoelectric substrate aimed at capturingthe image. Such changes in the respective positioning between differentcamera components result in unpredictable often deviations of thecamera's line-of-view from some initial position thereof taken asreference.

Therefore, when a TV camera constitutes a means for imitating themuzzle's axis in a boresight imaging device, it is very essential toprovide for a real time alignment of the TV camera line-of view.

While WO 02/27259 suggests rotating the boresight inside the muzzle fromtime to time as a part of calibration procedure, it ignores the abovedescribed problem according which the alignment of the camera should beverified on a real time basis, i.e. every time a muzzle's boresightingis to be carried out.

Moreover, the verification method suggested by WO 02/27259, i.e.rotating the boresight inside the muzzle, is a manual operation similarto that taken when calibrating boresighting devices having plain optics(with no TV camera) e.g. a telescope, as a means for imaging the actualmuzzle's axis.

An innovative calibration system and method, especially useful forboresighting equipment having TV camera as a means for imaging theactual muzzle's axis, has been developed by the inventor of the presentinvention.

Basically, the invention can be related to as an improvement inboresighting devices having a camera as a means for imitating muzzle'sboresight, the improvement is based on a pivotal coupling arrangementbetween an image-acquiring-unit, e.g. a CCD-camera, and a constructioncarrying the camera. The latter can be either attached, or removablyattachable, to a flat trajectory weapon's barrel. Animage-acquiring-unit pivotally coupled to a construction connected to,or removably attachable to a firearm barrel, will be referred tohereinafter also as “rotating camera”.

Due to the pivotal coupling arrangement, the rotating camera becomespivotable not only respective to the construction in which it residesbut also respective to the barrel to which the construction is attached.Accordingly, a correlation between a real time line-of-view of thecamera and an axis of the construction carrying the camera can easily beachieved by a technique including the following steps: aiming the cameraat a remote image origin for acquiring a reference image when the camerais in a first angular position respective to the construction carryingit; rotating the camera to a second angular position for acquiring acomparable image differing from the reference image in an angularorientation of the image; comparing the acquired images and determininga pixel or an array of a few adjacent pixels representing similarportion of the image origin in both acquired images; and marking saidpixel or a substantial center of said pixels' array by a reticle, e.g.crosshair, the crosshair (and any other indicator fulfilling a crosshairfunction, hereinafter will be also referred to a ‘crosshair’) thusrepresents the intersection between an image origin constituting atarget and between a line-of-view of the boresighting device. Assumingthat the boresighting device is properly attached to the weapon'sbarrel, the thus generated crosshair accurately imitates theintersection between the muzzle's axis and an image origin at which themuzzle is aimed. The crosshair of the boresighting equipment willtherefore be referred to as “muzzles crosshair”.

After carrying out said steps, a correlation between the muzzle and theweapon's sight can easily be verified by aiming the weapon towards atarget, and if necessary aligning the sight until a correlation betweenits crosshair and the muzzle's crosshair is achieved.

It can be appreciated that a pixel or an array of a few adjacent pixelsrepresenting similar portion of the image origin acquired in twoangularly spaced camera positions, is inevitably associated with aphotosensitive camera region aligned with all axis of rotation of thecamera. Said pixel or array of adjacent pixels will thus be referred toalso as “central pixel”.

An exemplary method for determining the central pixel is by determiningXY coordinations of a first point on the reference image representing areference point on the image origin; rotating the camera 180 degreesabout its axis of rotation and, acquiring a comparable image;determining on the comparable image XY coordinations of a second pointrepresenting said reference point; and determining the central pixel asa point in substantially the middle between said first and secondpoints.

Said technique, hereinafter “boresighting equipment setup technique” orsimply “setup”, can be carried out as a preliminary step of a weapon'sboresighting process, as a verification step during such process, orwhenever an alignment verification of boresighting equipment is desired.Due to the disposal of the needing to rotate the entire boresightingconstruction, and with the advantage that only the camera should berotated for the verification of boresighting equipment, it becomes veryeasy to carry out a successful boresighting process ending withsubstantially accurate correlation between weapon's sight and muzzle.

Preferably, the pivotal coupling arrangement includes a remotecontrolled motor configured to rotate the camera. According to someembodiments the motor is responsive to user's rotation commands.According to a best mode of operation, the setup steps are carried outautomatically through a computerized process. Such computerized processmay be initiated upon user's direct command. Alternatively it can beinitiated automatically either upon turning-on the boresighting deviceor several timed during its operation, e.g. every few seconds.

The computerized process either carried out by a dedicated control unit,or controlled by a weapon's computer, not necessarily requires arotation of the camera in a substantial angle in order to determining acentral pixel. Using appropriate computer algorithms which do notconstitute a part of the invention, two images acquired at two angularpositions of the rotating camera may be compared for determining acentral pixel, i.e. a pixel representing the same point of the imageorigin in both acquired images, even though the rotation angle of thecamera between acquisition of the two images is as small as e.g. about10-20 degrees, or e.g. about 25-45 degrees. Accordingly the motorconfigured for rotating the camera may be controlled for rotating thecamera a relatively small angular extent, e.g. about 30 degrees foracquiring angularly spaced images of an image origin. It can beappreciated that such angular rotation is small comparing to a rotationof 180 degrees which is usually performed upon manual setup of someknown boresighting equipment. Accordingly, although the motor of theinvented boresighting device may be controlled for rotating the camera180 degree, it is appreciated that a smaller angular rotation mayprovide for acceptable determination of a central pixel, and thus thetime duration needed for completing an automatic setup of the device ofthe present invention may be very short. The motor for rotating thecamera for such small extents can be a relatively small one and mayconsume very small amounts of energy. Accordingly, it can be batterypowered motor, and rechargeable batteries may be used, requiring notvery frequent recharging. A controller and a communication unit, as wellas the camera itself, may also be powered by the same battery.

The boresighting device of the present invention can thus be provided asa fully wireless and mobile unit.

The invention first relates to a boresighting device including arotating camera constituting a rotating image-acquiring-unit, and acamera carrier connected to or removably attachable to a firearm barrel.

The invention further relates to a boresighting system including aboresighting device having a rotating camera, a camera carrier connectedto or removably attachable to a firearm barrel, and a control unitlocated remotely from the boresighting device.

According to some embodiments the boresighting device includes a mobilemuzzle-adapter having a positioning arrangement configured to snugly fitthe inside of a firearm's muzzle such that the muzzle-adapter extendsalong a portion of the muzzle (preferably said portion is of a lengthnot less than three times the diameter of the muzzle) with thelongitudinal axis of the muzzle and the longitudinal axis of themuzzle-adapter substantially parallel to one another; at least oneimage-acquiring-unit having a line-of-view in parallel or close toparallel relationship with the longitudinal axis of the muzzle-adapter;and a communication unit for transmitting a signal indicative of animage acquired by the image acquiring unit, to a remote display unit;the system being characterized in that the image-acquiring-unit isconnected to the muzzle-adapter pivotally so as to allow angular motionof the image-acquiring-unit about an axis being, or parallel to, thelongitudinal axis of the muzzle-adapter.

It is appreciated that the rotation capabilities of the camera may servenot only for the mere setup of the boresighting equipment, but also forleveling the presentation of an acquired image origin regardless of thecurrent angular orientation of the muzzle-adapter about its ownlongitudinal axis.

According to some preferred embodiments the boresighting device of thepresent invention includes an innovative comfortable tighteningarrangement facilitating insertion and removal of the muzzle-adapter inand from the muzzle, especially useful but not limited to large caliberweapon. The tightening arrangement includes a lever handle operable by auser between a securing position and a releasing position and coupledmechanically to at least one tightening cam; the tightening cam beingmoveable by the handle between a tightening position in which the camprotrudes from the muzzle adapter to a first extent, and a releasingposition in which the cam is withdrawn into the muzzle-adapter or atleast moves to protrude from the muzzle-adapter a second extent smallerfrom said first extent. This tightening arrangement is advantageous overfitting arrangement currently used in boresighting devices, in that itallows for a considerably tightened fitness of the boresighting devicewhen in position for carrying-out a boresighting process, whileproviding for ease removal of the boresighting device, with negligiblefriction with the muzzle's walls, after completing the process.

The invention relates also to a setup method for camera-basedboresighting devices, the method includes aiming the boresighting devicetoward an image origin; activating a camera having a line-of-view foracquiring from the image origin a reference image taken at a firstangular position of the camera; rotating the camera about an axisparallel or close to parallel to the line-of-view and acquiring acomparable image from the image origin taken at a second angularposition of the camera; comparing the acquired images and determining apixel or an array of a few adjacent pixels representing similar portionof the image origin in both acquired images; and marking said pixel or asubstantial center of said pixels' array by a crosshair.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carriedout in practice, a preferred embodiment will now be described, by way ofnon-limiting example only, with reference to the accompanying drawings,in which:

FIG. 1 is a perspective view of an exemplified boresighting deviceaccording to the present invention.

FIG. 2 is a perspective exploded view of a camera module according to anexemplified embodiment.

FIG. 3 is a cross section view through the boresighting device 1illustrated by FIG. 1.

FIG. 4 is front view of the boresighting device I illustrated by FIG. 1.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a perspective view of a mobile boresighting device 1 accordingto some embodiments of the present invention. The boresighting device 1has a construction 2 constituting a muzzle-adapter configured to beremovably mounted into a weapon's muzzle (not illustrated) with apredetermined imaginary axis 3 of the construction lying substantiallyparallel and immoveable respective to the centerline axis of the muzzle(i.e. the boresight). A rotating-camera 4, constituting a rotatingimage-acquiring-unit, in this exemplified embodiment a digital videocamera, is accommodated in the construction, inside apivotal-coupling-arrangement 5 which is shown in more detail in anexploded view in FIG. 2.

The camera focal is configured to infinity thus needing no zoom forcovering the range 500-1,200 meter, which is the relevant range forboresighting flat trajectory weapons of all types and calibers. Havingan improved resolution, the camera requires no external optics. Based onthe high resolution of the camera (e.g. between 3-8 Mega pixel), anelectronic digital-zoom addresses the zooming requirements.

The rotating-camera 4 is configured to generate a machine readablesignal indicative of the images it acquires from an image origin. Thesignal may then be processed and/or used for displaying a picture of theimage-origin on a screen (not shown).

The rotating-camera 4 has an image-field-of-view 7 having anaxis-of-symmetry 6 (some times referred to in this specification as the“line-of-view”). The pivotal coupling arrangement 5 allows theimage-acquiring-unit to pivot about an axis being or lying parallel tothe imaginary longitudinal axis 3 of the construction. Pivoting thecamera a predetermined angle about the longitudinal axis 3 of theconstruction will cause a respective angular pivoting of an acquiredimage of an image-origin about a symmetry point of the picture, suchthat every acquired point of the image-origin will be represented in thepicture with an angular shift from its location in the picture prior thepivoting. In this regard the symmetry point itself is exceptional, sinceit would not change its original location in the picture in response topivoting the image acquiring unit about its axis of symmetry.

It is appreciated that when the image acquiring unit 4 is accommodatedin the construction with the line-of-view 6 lying parallel to theimaginary axis of the construction 3, and the constructions axis ofsymmetry 3 lays parallel to the muzzle's centerline axis (not shown),then the line-of-view 6 of the image acquiring unit 4 satisfactoryrepresents the muzzle's boresight.

When the image acquired by the image acquiring unit is displayed as apicture on a screen, its symmetry point can be indicated by a virtualreticle (such as a cross-hair) superimposed into the picture with anindication point of the reticle merged with the picture's symmetrypoint.

Assuming now that a weapon's sight is aimed towards a target with across-hair of the sight indicating the center of the target,boresighting of the weapon may be approved if the virtual reticle in apicture acquired by the device of the present invention when beingmounted in the weapon's muzzle, will also indicate to the same point.

However, as indicated in the summary of the present invention, theline-of-view of a digital camera unpredictably changes through time as aresult of different factors. Accordingly, and in order to maintaincorrelation between the varying line-of-view and the muzzle's boresight,a setup procedure of the boresighting device 1 will be carried outeither automatically or upon user's demand, sufficiently often so as toprovide for reliability. Since the setup steps are performedautomatically, and prolong several seconds and even less, it can becarried out on a real-time basis without any substantial burden.Whenever a deviation of the camera line-of-view 3 from the constructionaxis 3 is identified during the setup, the crosshair will automaticallybe re-positioned to merge its indication point with the center of thepicture.

The construction 2 may be of any design suitable for snugly fittinginside a muzzle for providing a reference axis imitating the muzzle'sboresight. The construction 2 has a positioning arrangement comprisingat least six contact areas configured to contact the cylindrical innerwall of a muzzle in at least six remote points so that when themuzzle-adapter 2 is inserted into a muzzle, it will fit into it with thesix contact areas in a friction contact with the inside of the muzzlewall. The exemplified construction is an envelope comprising a firstportion 9 for accommodating an image-acquiring-unit such as a videocamera 4, and for positioning said image-acquiring-unit in appropriateorientation inside the muzzle of a flat trajectory weapon. Two contactmembers 15 (constituting two of said six contact areas), slightlyprotrude from the envelop portion 9, and are intended to contact and bepressed to the insides of the muzzle's wall in respective two locations.The envelope further comprises a second portion 10 located remotely fromthe first portion of the envelope so as to form together with the firstenvelope's portion an elongated construction 2 having a length of aboutat least three times the inner diameter of the muzzle. This is in orderto minimize inaccuracies resulting from inaccurate positioning of theboresighting device. Additional two contact members 16 (constitutingadditional two of said six contact areas), slightly protrude from theenvelop portion 10, and are intended to contact and be pressed to theinsides of the muzzle's wall in respective two locations. The envelopeportions 9 and 10 are bridged through a mid portion 11. The wall of themid portion is perforated by holes 12, thus weighs less than might havebeen without the perforation, useful for reducing the total weight ofthe boresighting device. The construction has a flange 13 formed nearthe end of the envelope portion 9, for restricting slippage of thedevice to the far depth of the muzzle, and to help in positioning thedevice properly. A lever handle 14 facilitate insertion and removal ofthe device to and fro the muzzle, as will be further detailed in thedescription of FIG. 3. As will be explained, the lever handle 14controls two cams 30 and 31 (not shown in this Fig.) located at theunderbodies of the envelope portions 9 and 10, respectively, said camsconstituting the remaining two of the six mentioned contact members.

FIG. 2 is a perspective exploded view of a camera module 18 to beaccommodated inside the muzzle-adapter illustrated by FIG. 1. The cameramodule 18 includes a high resolution infinite focal small CCD camera 4.The camera includes a wireless communication unit 4 a and plain optics 4b. The camera is accommodate in a pivotal-coupling arrangement 5comprising a housing 5 a having outer dimensions matching the innerdimensions of the envelope portion 9 of the construction 2 shown in FIG.1, such that the imaginary axis 19 of the camera module will merge withthe longitudinal axis 3 of the construction 2. The camera 4 is coupledto the housing 5 a through camera holder 20 which in turn being coupledto the interior of a nose portion 5 b of the housing 5 a, by means of apair of ring-shape bearings 21 and 22. The camera holder 20 is geared toan electrical motor 23. Upon rotation of the motor shaft, the cameraholder 20 will rotate and so will rotate the camera 4 held by.

FIG. 3 is cross section view through the boresighting device 1illustrated by FIG. 1. The device comprises a construction 2 having afirst and a second envelop portions 9 and 10, respectively, connectedthrough a mid envelop portion 11, perforated by a plurality of holes 12.The first envelop portion 9 accommodates a pivotal-coupling-arrangement5, coupling between a rotating-camera 4 and the first envelop portion 9.

The camera is rotated upon rotation of the shaft of electrical motor 23.A tightening arrangement comprising a lever handle 14 operable by a userbetween a securing position and a releasing position is also shown. Thelever handle 14 is coupled mechanically through force transmission bar25 and through latching members 26 and 27 to a front and a reartightening cams 30 and 31, respectively. The tightening cams aremoveable by the handle 14 between a tightening position in which the camprotrudes from the muzzle adapter to a first extent as indicated bydotted lines 30 a and 31 a, and a releasing position in which the cam iswithdrawn into the muzzle-adapter (and alternatively at least moves toprotrude from the muzzle-adapter a second extent smaller from said firstextent).

FIG. 4 illustrates a front view of the embodiment of the boresightingdevice 1, illustrated by FIG. 1. The front portion of the camera optics46 is seen through an opening made in the nose 5 b of the pivotalcoupling arrangement 5, which is accommodated in the construction 2which in this Fig. is hidden behind the flange portion 13. The leverhandle 14 of a tightening arrangement is seen in a releasing position.After placement of the muzzle-adapter inside a weapon's muzzle thelever-arm is moved upwardly by a user in order to secure the deviceinside the muzzle by pushing the cams 30 and 31 to protrude out of theenvelop so as to contact the interior of the muzzle wall and press theenvelop tightly between opposite sides of the circular muzzle's wall.

It should be noted that the same camera module may be useful for anyweapon type and caliber, since the same camera module comprising arotating camera according to the present invention may be coupled tomuzzle-adapters of different shapes and sizes. Accordingly, the samesystem, remote controlling units, and setup algorithms may be used forvarious weapon types, by only changing the type of muzzle-adapter foraddressing the requirements of the specific weapon.

1. A boresighting device, comprising a rotating camera and a cameracarrier connected to or removably attachable to a firearm barrel.
 2. Aboresighting device according to claim 1, further comprising electricalmotor coupled to the rotating camera.
 3. A boresighting device accordingto claim 2, wherein the motor being remotely controlled.
 4. Aboresighting device according to claim 1, further comprising wirelesscommunication unit.
 5. A boresighting device according to claim 1,wherein the camera is coupled to a weapon's barrel or to amuzzle-adapter attachable to a weapons barrel, through a ring-shapedbearing.
 6. A boresighting device according to claim 1, furthercomprising a tightening arrangement comprising a lever handle operableby a user between a securing position and a releasing position andcoupled mechanically to at least one tightening cam; the tightening cambeing moveable by the handle between a tightening position in which thecam protrudes from the muzzle adapter to a first extent, and a releasingposition in which the cam is withdrawn into the muzzle-adapter or atleast moves to protrude from the muzzle-adapter to a second extentsmaller from said first extent.
 7. A boresighting device according toclaim 1, further comprising a control unit located remotely from theboresighting device.
 8. In a boresighting device having a camera as ameans for imitating muzzle's boresight, the improvement comprising apivotal coupling arrangement between the camera and a constructioncarrying the camera.
 9. Boresighting system comprising a boresightingdevice having a rotating camera, a camera carrier connected to orremovably attachable to a firearm barrel, and a control unit locatedremotely from the boresighting device.
 10. Setup method for camera-basedboresighting devices, the method includes aiming a boresighting devicetoward an image-origin; activating a camera having a line-of-view foracquiring from the image origin a reference image taken at a firstangular position of the camera; rotating the camera about an axisparallel or close to parallel to the line-of-view and acquiring acomparable image from the image origin taken at a second angularposition of the camera; comparing the acquired images and determining apixel or an array of a few adjacent pixels representing similar portionof the image origin in both acquired images; and marking said pixel or asubstantial center of said pixels' array by a crosshair. 11.Boresighting device having a camera as a means for imitating a muzzle'sboresight, the camera being characterized by an invariable zoom and afocal infinity.